[PDF - ENG] Six Sigma And Lean Thinking

Symbols
Standard deviation = σ Average = µ Normal distribution = N(µ,σ)
Definitions
Sigma is: The square root of the variance What sigma means is the …
Six Sigma
To accommodate six times the standard deviation value in between the manufacturer’s specification limits
Definitions cont.
The universal formula
µ + k⋅ σ
The k*sigma importance
K 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 Probability 0.841344746068543 0.933192798731142 0.977249868051821 0.993790334674224 0.998650101968370 0.999767370920966 0.999968328758163 0.999996602326866 0.999999713348346 0.999999981010436 0.999999999013412 0.999999999959840 0.999999999998720 0.999999999999968 0.999999999999999 ARL nonconforming 6.30 14.97 43.96 161.04 740.80 4,298.69 31,574.39 294,319.07 3,488,554.79 52,660,502.10 1,013,594,634.89 24,900,406,809.35 781,332,343,402.24 31,383,969,528,714.30 1,501,199,875,790,170.00
Example cont.
µ=0 σ=1 0.8 USL = 2 0.6 LSL = -2
0.4
0.2
0
4 −4
2
0 x , x , LSL , USL
2
4 4
Example cont.
What can we do to improve the process? Reduce the variance thereby reducing the standard deviation. How? Slow the extrusion rate.
What are constraints? What is efficiency? What is productivity? What is added value? What is cost efficient? What is “lean”? What is thinking?
Vision
Definitions
Green belt Black belt Master black belt
Organizational levels cont.
Green belt Black belt
Organizational levels cont.
Master black belt
Lean Thinking
Introduction
Quote
“Common sense is the least common of senses.” José Duprey
Lessons learned
QUESTIONS?????
Example cont.
µ=2 σ = .5 USL = 2 LSL = -2
0.8
0.6
0.4
0.2
0
4
2 , ,
0 ,
2
4
Example cont.
What can we do to improve the process? Modify something else What? The melting temperature. How? A higher temperature.
Organizational levels
Since Six Sigma is very famous and it is one the fashion statements in the industry, levels have been made to differentiate how much knowledge a person has in six sigma
Example cont.
The answer should look in the end something like this.
0.8
0.6
0.4
0.2
0
4
2
0 x, x, LSL, USL
2
4
Lessons learned
Six Sigma doesห้องสมุดไป่ตู้not have a unique way of solving problems in the industry. It requires experimentation, studies, and good applied Engineering to solve the problems. Six Sigma is a tool that if applied correctly the quality of the product is guaranteed by showing if non-conforming products are going to happen or not.
Ej.
High temperature and high extrusion rate High temperature and low extrusion rate Low temperature and high extrusion rate Low temperature and low extrusion rate Change the type of plastic Among others
Agenda
Six Sigma
Introduction Vision Definitions Quote Lessons learned
SIX SIGMA
Introduction Six Sigma
What is a process? What is Quality Control? What means to say, “ a process’ quality is in control”? What is a normal distribution? What is “Sigma”? What is a manufacturer’s specification limit?
Six Sigma and Lean thinking
Miguel Lopez M&D Consulting Agency
Agenda
Six Sigma
Introduction Symbols Definitions The k*sigma importance Example Organizational levels Lessons learned
0.2
2
0 x, x, a, b, c
2
4
Definition cont.
Specification limit
It is the range of values considered acceptable in the manufacturing of a specific product for a specific characteristic.
n
σ
∑
i=1
( Xi − µ)
n
2
Definitions cont.
Normal distribution 0.8 µ=0 σ=1 0.6 Blue is N(0,1) Red is cummulative 0.4 N(0,1)
Green, brown, and pink is 1, 2, and 3 σ 0 distances respectively 4
Example cont.
µ = -1 σ = 1.5 USL = 2 LSL = -2
0.8 ) 0.6
0.4
0.2
0
4
2
0
2
4
Example cont.
Still wrong. What next? We have to continue trying different combinations
Example
Extrusion of plastic Assume we are interested in a plastic extrusion process. We can control the temperature at which the plastic is melted and the rate of extrusion. The manufacturers limits are µ+/-2mm The actual situation is represented in the next slide.